STATUS REPORT ON THE ACTIONS
ARISING FROM THE STUDY OF RADIOLOGICAL CONTAMINATION OF THE WONDERFONTEINSPRUIT
CATCHMENT AREA (WCA)
STATUS REPORT ON THE ACTIONS
ARISING FROM THE STUDY OF RADIOLOGICAL CONTAMINATION OF THE WONDERFONTEINSPRUIT
CATCHMENT AREA (WCA)
1. Introduction
The National Nuclear Regulator (NNR) commissioned a
study in November 2006 to assess the radiological impacts of mining activities
in the Wonderfonteinspruit Catchment Area (WCA). This study was conducted as a
screening assessment intended to confirm the existence of possible radiological
impacts, to be followed by a more comprehensive study to determine the extent
of the problem and inform what corrective measures will be required should
existence of radiation contamination be confirmed. The screening studies are by
definition and nature limited in time and scope.
Following the outcome of the screening assessment the
NNR issued directives to the holders operating in the vicinity of the WCA to
among others:
a)
Immediately
conduct a comprehensive investigation in order to determine the full extent of
the radioactive contamination arising from mining operations over the WCA and
provide a report to the NNR with respect to the findings of such an
investigation.
b)
Provide
a plan of action for the immediate control of the area to prevent exposure to
members of the public.
c)
Review
and update their environmental monitoring programme in light of the indications
of radioactive contamination in the WCA.
d)
Provide
the NNR with a schedule for the review and update the Public Hazard Assessment
of the mine, taking into account the leading exposure pathways as identified
through the study.
The holders
have responded to the directives as required by the NNR and their responses are
summarized in section 2 below.
2. Status
of actions taken by the NNR
The NNR
published the results of the study to all the relevant interested and affected
parties including the authorization holders in the vicinity of the WCA. These
holders were then issued with directives to undertake certain corrective actions,
which included short term and long term actions. These corrective actions are summarized
below:
|
Corrective Actions |
Status |
|
|
Short Term |
Conduct
a comprehensive investigation in order to determine the full extent of the
radioactive contamination arising from mining operations and provide a report
to the NNR |
Not all
the holders submitted the required reports. Of the submitted reports, there
is a clear indication that a comprehensive assessment need to be done as
little additional information was provided. For those holders that did not
submit the reports as required, time was given until |
|
Restrict
access of the animals and the public or use of water for irrigation purposes
to the identified sites, while further investigations were being carried out. |
These
actions have been conducted on all sites within the scope of authorisation of
the holders and the NNR is satisfied with the reports submitted. Confirmatory
surveys have been conducted by the NNR on these sites. Sites
not within the holder’s scope of authorisation which were affected by
contamination requiring access restriction will be identified and necessary
protective action taken. |
|
|
Long Term |
Review
and update environmental monitoring
plans in light of the indications of radioactive contamination in the WCA |
No reports
were provided. Most holders indicated that more time will be required
to finalise these reports as they have to take into account the seasonal
variations, etc.. The environmental monitoring programmes will be developed
to take into account |
|
Provide
a schedule to review and update the Public Hazard Assessment of the mine,
taking into account the leading pathways as identified through the study |
No
schedule was provided for the review of the PHAs. This can be addressed as
part of the Authorization Change Request (ACR). The NNR will address this
during the Project Review Meeting in Jan/Feb 2008. This should take into
account all the deficiencies identified by the study and requirements for
seasonal variation monitoring. The
overall timescales will for the review of the PHAs will be discussed at this
meeting. A review
on the sediments results confirms that indeed there are elevated levels of
radiation in some of the sediments samples taken from the dams along the WCA. |
|
3. Assessment and analysis of the
agricultural produce in the vicinity of the WCA
While the
calculated doses in certain sampled points were above regulatory limits, it is
important to determine directly the actual doses in the produce grown in the
area. The NNR collected samples of vegetables (onions, asparagus and oats) and
fish in the area and sent these for analysis. The projected doses from the
samples taken indicated that the total doses from some the samples taken are
above the dose constraints and dose limit of 250μSv/a and 1mSv/a
respectively and are of safety concern from a radiological point of view. A
more detailed and comprehensive analyses of milk and meat from cows grazing
along the WCA will be undertaken as part of the comprehensive assessment.
The terms
of the 1year and 17 year old age groups
the table below, indicates these to be the critical age group that will
consume these agricultural products (samples taken) grown in the WCA. It should
be noted that, these are not actual exposures but are calculated doses based on
certain consumption rates and occupancy factors.
|
|
Dose in μSv/a |
|
|
Samples taken |
1year |
17years |
|
Oats |
2300 |
712 |
|
Asparagus |
161 |
61 |
|
Onions |
630 |
236 |
|
Barber |
4.46 |
16.9 |
|
Karp |
9.90 |
32.4 |
|
Total Dose |
3106 |
1058 |
Samples of agricultural produce taken by
holders
|
|
Dose in μSv/a |
||||
|
Samples taken |
1year |
2-7 years |
12-17 years |
17years |
|
|
Meat |
34.8 |
29.4 |
21.4 |
16.1 |
|
|
Fish |
12.20 |
17.5 |
15.4 |
61 |
|
|
Total dose |
47.0 |
46.9 |
36.8 |
46 |
|
Furthermore, vegetables samples like cabbage,
beetroot, spinach, Italian-rye and oats have been send for analysis and the
outcome of the analysis is still awaited.
4. Water samples analysis in the WCA
The trend analysis done show that for all the age
groups the potential doses for 2007 are the lowest of the years, with the
highest exposure in the year being 0.155mSv/a for the age group 12-17. This is
consistent with other reports which indicated that drinking water is safe from
a radiological point of view.
|
Year |
Age 1-2 |
Age 2-7 |
Age 7-12 |
Age 12-17 |
Adult |
|
|
|
|
|
|
|
|
2007 |
0.082 mSv/a |
0.060 mSv/a |
0.062 mSv/a |
0.155 mSv/a |
0.071 mSv/a |
5. Sediments samples analysis in the WCA
Sediments
sampling was conducted in the dams along the WCA on 100 x100 m grid by the
Wonderfontein Action Group (WAG). That included Middel Vlei, Waterway, Big,
Coetzee, Visser 1, Visser 2, Harry’s and the Klerkskraal Dam. There are some
hot spots identified in certain sampled sections of the dams up to about
300Bq/g. Various sediments extraction techniques should be investigated for
implementation as part of the remediation measures to be adopted when
conducting the comprehensive assessment.
6. Soil contamination survey along the
banks of the WCA
Some of the authorization holders
operating in the vicinity of the WCA conducted a radiological contamination
survey on the soil along the banks of the spruit using an Exploranium GR320 NaI
crystal. This investigation was done to determine whether there was any
contamination of soil arising from runoff and seepage from slimes dams on the
banks of Wonderfonteinspruit Catchment Area. The area surveyed was about 9.3ha
and stretched from the Donaldson dam to the Randfontein Estates Gold Mine.
Following the survey it was discovered that an area of 0.2Ha was contaminated with slimes from historic
slimes spills, the site was identified adjacent to the Wonderfonteinspruit on
portion 90 of the Luipaardsvlei 243 IQ. The activity levels in the contaminated
area ranged from 0.5Bq/g to 1.84Bq/g. This accounted for 34% of the total surveyed
area. Furthermore, about 2.0 ha of land was identified as contaminated in the
Coetzee farm (a privately owned land). It is expected that the contaminated
area will be cleaned by end December 2007.
7. Conclusion
The study
undertaken by the NNR has confirmed the presence of radioactive contamination
in the WCA. Regulatory actions were
taken to ensure that people and animals are protected. Preliminary results of
analyses conducted on produce grown in the area have indicated that the dose
levels are of radiological concern to the regulator. The study has also
highlighted the need for all the regulators to work closely together since the
contamination includes non radiological contaminants such as heavy metals and
salts.
The issues
involved in the contamination in the Wonderfontein Catchment Area are complex.
There are challenges that have been identified that would have to be specifically
addressed. These challenges relate to:
·
Areas
that fall on privately owned land outside the scope of the authorizations
issued by the NNR
·
The
assigning of liability for control measures and the costs associated therewith
when contamination is in areas not covered by the scope of the authorisation.
·
The
need for an integrated approach to remedial measures implemented due to the
fact that the contamination in the water is not limited to radioactive material
but also contains other heavy minerals as well as salts. To this end there is need for collaboration
and cooperation with other regulators such as DEAT, DME and DWAF.
·
The
financial implications associated with the cost of conducting a detailed and
comprehensive assessment
8. Way Forward
The
result submitted by the holders, indeed confirmed that a comprehensive
assessment should be conducted. The following should be taken into
consideration in the event such a study is conducted:
·
An
integrated approach for remedial measures should be adopted due to the fact
that the contamination in the water is not exclusively radiological but also
contains other heavy minerals as well as salts
·
A
detailed comprehensive study on WCA, which should include a proper land use
survey, should be conducted. That would also take into account the seasonal
variations.
·
Other
relevant regulators, like DWAF, DME and DEAT, should be involved in the
determining of remedial or other actions to be undertaken. This will be done through cooperative
agreements that exist between the NNR and these identified organs of state. A
letter is awaited from the DME in respect to the coordination of this issue.
The approach from other regulators is that uniformity on compliance
requirements from different organs of state must be effected.
·
Alternative
methods of cattle watering, such as having cattle drink from troughs must be
investigated and implemented at dams where elevated levels of radioactive
contamination have been detected in the sediments, while the comprehensive
assessment is being carried out. Cattle farmers have requested the surrounding
mines to implement this action.
·
Regular
interaction with various stakeholders such as mining operators, local
authorities and affected communities to address the areas of concern. The establishment of a NNR public
communication forum is currently being considered. What are the timescales for
establishing this forum?-(There has been consultation with various NGO and
community forums in trying to establish this forum. In the interim the NNR has
participated in the DWAF public forums in order to provide feedback to the
affected communities.
·
A
number of studies have been conducted on the WCA, a detailed literature review
should be conducted
·
Epidemiological
studies should also be considered as part of the comprehensive assessment
·
More
sampling should be done on the agricultural produce like vegetables, feedstock,
and grains.
·
Various
sediment removal techniques should be investigated as part of the comprehensive
assessment
Additional comments:
The results as indicated in
section 3 above related to the projected
doses from the samples taken indicated that the total doses from some of the
samples taken exceed the dose constraints and dose limit of 250μSv/a and
1mSv/a respectively and are of safety concern from a radiological point of
view. Farmers in the area have been notified and of this matter and the NNR
have required that alternative arrangements be made regarding the growing
practices.
Furthermore the results of
section 6 “following the
survey it was discovered that an area of 0.2Ha was contaminated with slimes from historic slimes spills, the site was
identified adjacent to the Wonderfonteinspruit on portion 90 of the
Luipaardsvlei 243 IQ. The activity levels in the contaminated area ranged from
0.5Bq/g to 1.84Bq/g. This accounted for 34% of the total surveyed area.”
The activity concentration levels
indicated above are above the exclusion levels of the Safety Standards and
Regulatory Practices and these seem to be present in a public area along side
the Wonderfonteinspruit. Ongoing efforts are in place to restrict access to members of the
public.
Remarks:
It is expected that the comprehensive
study should commence in Jan/February 2008 with all the relevant stakeholders
been consulted and assigned their responsibilities.